A large variety of valves for use with vehicles' fuel tanks are known, among which are of more relevance with respect to the present invention those fitted with two or more valve assemblies.
For example, U.S. Pat. No. 6,675,779 discloses a tank venting apparatus or a fill-limit and tank ventilation valve is disclosed for use with a fuel tank. The valve has a housing which contains a first valve assembly, second valve assembly, third valve assembly and fourth valve assembly. The first valve assembly primarily communicates with the fuel tank. The fourth valve assembly communicates with a vapor recover canister and a filler neck to the tank. The first valve assembly also communicates with the third valve assembly and the second valve assembly. The second valve assembly generally communicates with the first valve assembly and the third valve assembly. The third valve assembly communicates with the first valve assembly, second valve assembly and fourth valve assembly. The third valve assembly prevents passage of liquid fuel from the tank to the canister. The fourth valve assembly manages flow from the valve.
U.S. Pat. No. 6,240,950 is directed to a vapor control valve includes first, second, and third valves and a housing formed to include first, second, and third chambers and first, second, and third apertures. The first valve is formed to include a vent aperture and is movable relative to the first aperture to partially close the first aperture to limit flow from the first chamber to the second chamber through the first aperture. The second valve is movable relative to the first valve to open and close the vent aperture and cooperates with the first valve to close the first aperture to prohibit flow from the first chamber to the second chamber through the first aperture in response to rising liquid fuel. The third valve is biased to normally close the third aperture and configured to open the third aperture in response to pressurized fuel vapor to permit flow from the second chamber to the third chamber through the third aperture. The vapor control valve includes a blocker coupled to the second valve and configured to extend through the first aperture into the third chamber to contact the third valve to maintain closure of the third aperture by the third valve when the first aperture is closed by the first and second valves.
U.S. Pat. No. 5,797,434 is concerned with an onboard vapor recovery system for a vehicle fuel system having a fuel tank, a filler neck dynamically sealed by high pressure fuel flow from a filler nozzle, and a vapor recovery apparatus such as a carbon canister. The system preferably uses an inventive liquid level operated control valve which shuts off refueling with a two-stage closing operation providing an initial soft shutoff and a final shutoff. The system also preferably includes a valve in the fuel tank to maintain a predetermined pressure head sufficient to hold the system closed against further refueling at least temporarily, and a positive action, one-way check valve in the lower end of the filler pipe to prevent spitback of fuel from the pressurized tank once refueling has ceased.
Another arrangement directed to a over-filling preventing valve is disclosed in U.S. Patent Application No. 2003/0189110 directed a fuel valve includes an upper chamber communicating with a ventilation passage of a canister; a lower chamber to be disposed inside a fuel tank; a communicating port between the upper chamber and the lower chamber; and a float member disposed in the lower chamber for blocking the communicating port when fuel flows into the lower chamber. The lower chamber includes a one-way valve formed at a bottom thereof for allowing the fuel to flow out only through the one-way valve, and a fuel inlet formed in a side wall of the lower chamber. When a fuel level inside the fuel tank reaches the main fuel inlet, the fuel flows into the lower chamber to raise the float member. As a result, an internal pressure of the fuel tank increases, so that a sensor at a fueling nozzle side can detect that the fuel tank is filled-up.
U.S Patent Application No. 2002/0144730 discloses a vent apparatus is adapted for use with a fuel tank to control venting of fuel vapor from the fuel tank. The vent apparatus comprises a fuel vapor vent outlet to discharge fuel vapor from the fuel tank. The vent apparatus comprises a normally open first valve module to serve as a fuel fill limit valve and close when the liquid level in the tank reaches a predetermined fill limit and a normally open second valve module to serve as a fuel fill limit valve and close when the liquid level in the tank reaches the predetermined fill limit. The first valve module and the second valve module cooperate to block communication between the fuel tank and the fuel vapor vent outlet when the vent apparatus is positioned in a non-tilted orientation relative to a horizontal and the level of liquid fuel in the fuel tank reaches the predetermined fill limit to close both valve modules.
U.S Patent Application No. 2004/0003843 is directed to a valve where a first seal seat is disposed in a first passage of a case. The first float valve body is disposed in the case and closes the first seal seat in response to the liquid level of the fuel. The second seal seat is disposed vertically above the first seal seat, in a second passage of the case. The second valve body is disposed on one side of the second seal seat communicating to the outside of the second passage, with being resiliently urged upwards from below. The second float is disposed in the case and regulates an upper end position of the second valve body to open the second valve seat in response to movement of the liquid level of fuel at least until the liquid level is higher than the liquid level at which the first float valve body closes the first seal seat.
U.S. Pat. No. 5,738,132 discloses a roll over vent valve (ROV) comprising a housing formed with an inlet and an outlet, said outlet comprising a slit-like aperture, and a float member located within the housing axially displaceable between said inlet and said outlet. An elongated flexible closure member strip is anchored at one end thereof adjacent said outlet and a spring biases the float member in direction of said outlet. The arrangement is such that the spring biasing force together with buoyancy forces acting on the float member tend to press the membrane strip into sealing engagement with the outlet aperture and gravity forces acting on the float member tend to displace the float member away from the outlet so as to progressively detach the strip from sealing engagement with said outlet.
However, displacement of the float member into the sealing position occurs rapidly wherein said outlet aperture is spontaneously sealed as the closure membrane strip rests against a valve seating of said outlet. In addition, disengagement of the closure membrane strip from the valve seating might be somewhat delayed, in particular under high pressure. Even more so, this valve is not suitable for discharge of fuel vapor at high flow rates.
It is an object of the present invention to provide a two-float, multi functional valve, for use in vehicle fuel tanks which valve simultaneously serves as an over filling interdiction valve (OFI), a vapor recovery valve, a roll over valve (ROV), a filling limit vent valve (FLVV), an onboard refueling vapor recovery valve (ORVR) and as vent valve.
It is a further object of the present invention to provide a valve of improved design wherein displacement into its sealing position does not generate a pressure shockwave within the fuel tank on the one hand, and, on the other hand, provides opening of the valve, even under essentially high pressure.